Method of dyeing natural and synthetic fibers

ABSTRACT

A TEXTILE DYEING PROCESS WHEREIN A METHYLOXOLANE IS EMPLOYED AS A CARRIER ALONE AND IN COMBINATION WITH OTHER KNOWN CARRIERS.

United States Patent 3,667,900 METHOD OF DYEING NATURAL AND SYNTHETIC FIBERS Averal T. Trimble, Jr., Charlotte, N.C., assignor to CaroChem Corporation, Charlotte, N.C. No Drawing. Filed Nov. 10, 1969, Ser. No. 875,557 Int. Cl. D0611 5/04 US. Cl. 8-173 2 Claims ABSTRACT OF THE DISCLOSURE A textile dyeing process wherein a methyloxolane is employed as a carrier alone and in combination with other known carriers.

This invention relates to improvements in textile dyeing, and particularly, carrier dyeing of natural and synthetic fibers.

Textile dyeing in the broad sense in which it is understood and practiced, is the exposure of fibers to one, or more, of a large group of chemical entities known as dyestuffs and dyestuff intermediates. At many particularly active sites along a fiber, these chemical entities absorb and penetrate, more or less deeply, into the fiber. The object of textile dyeing is to produce fibers, dyed to one of a wide variety of colors and shades, which exhibit wash fastness, light-fastness, crock-fastness, luster, and other desirable characteristics. Current practices utilize many kinds of fibers, such as cotton, wool, silk, and other natural fibers; viscose rayon (derived from regenerated cellulose), acetate rayon (in which regenerated cellulose is partially or completely reacted chemically to produce cellulose acetate), and other natural polymers; polyamide (such as nylon 6 or nylon 6.6), polyacrylonitrile, polyester (derived from a dihydric alcohol and terephthalic acid), polyurethane, and other synthetic polymers; synthetic copolymers (such as the copolymer of acrylonitrile and vinyl chloride), and especially blends of two or more of the fibers described above (such as polyester and wool). Current practices also utilize many classes of dyestufls, such as direct dyestuffs, disperse dyestulfs, premetallized dyestuffs, acid dyestuffs, basic dyestuffs and vat dyestuffs.

For rapid dyeing to give firm bonding, thorough penetration and efiicient discharge of dyestufi from the dye bath, particular physical conditions in the exposures above must be met. High temperatures and frequently high pressures must be used. Vigorous agitation is often necessary, exerted, viz, by repeated passage of woven fibers through a dye bath or pumping dye-liquor through packages of fibers. The exposure of the fiber to the dyestuff or intermediate ordinarily takes place in an aqueous dye bath. However, removing the fibers from the bath and treating them with vapors of water and special chemical agents to improve the fastness or penetration is also known. Utilizing a non-aqueous dye bath has been reported, but has not yet found a wide acceptance.

In carrying on the various operations, which have been described above (i.e., exposing the fiber to dyestulfs or intermediates; subjecting the exposed fibers to further physical and chemical treatments), a large group of auxiliary chemical agents have proven to be necessary or desirable. These are designated broadly as dyeing assistants. For example, the dispersion of insoluble dyestuffs in a liquid medium usually requires dispersing agents. Keeping dyestuffs in suspension often requires thickening agents. Facilitating uniform adhesion and penetration of dyestuffs is the work of leveling agents, etc. These auxiliary functions require the addition of a number of chemical com pounds to the dye bath, as illustrated in the examples below.

It should be noted that although generally accepted practice often stipulates that a chemical compound be added for a particular auxiliary function, it is well known that the compound may assist in other functions, or act synergistically. In particular, a common auxiliary in the dyeing of synthetic hydrophobic fibers such as nylon and polyester fibers is benzyl alcohol. In small amounts, benzyl alcohol functions as a dispersing agent in the dispersion of dyestuffs in the dye bath, as a leveling agent in promoting uniform dyeing, and as a penetration assistant in activating the dye-sites on the fiber and facilitating the penetration of the dyestuff. An auxiliary that performs one or more of these functions is usually called a carrier.

It is important also to note that, in addition to their beneficial functions, many carriers can exert deleterious effects in textile dyeing. Thus, the deleterious effects frequently limit'the amount of a particular assistant that can be used in a dye bath. For example, in the known process of multicolor dyeing of bulky nylon yarn wherein the yarn is knit into a fabric, printed, and then de-knit, it is well known that when a minimum of 2% benzyl alcohol is incorporated with dyestuffs and other auxiliaries in the print paste, rapid dyeing to give deep shades with excellent penetration and strong fibers results. However, when benzyl alcohol is used in excess of 4%, there is physical weakening of the fibers and appreciable degradation of the fibers through a solubilizing action. In even larger proportions benzyl alcohol can destroy the fiber character altogether. Even at a level of 2% benzyl alcohol stitfens and flattens the nylon fibers, which results in a significant reduction in the bulkiness of the yarn.

Many, if not all, of the more effective carriers now in general use in textile dyeing possess various other significantly undesirable properties such as lack of solubility in aqueous media and toxicity. For the most part, if not entirely, such carriers are aromatic compounds such as benzyl alcohol, o-phenylphenol, methyl salicylate, xylene, toluene, trichlorobenzene, bi-phenyl, naphthalene and various derivatives thereof.

It is the object of this invention to provide improved and superior carriers and/or superior combinations of carriers for the dyeing of natural and synthetic fibers.

It is another object of this invention to provide a carrier which is water-soluble to thereby insure uniformity of carrier-containing aqueous dye bath compositions, and which, when used in combination with other insoluble car- -riers improves the solubility and/ or dispersability thereof in the aqueous dyeing medium.

It is still another object of this invention to provide a carrier which is non-toxic and extremely safe for use.

In accordance with the invention, a clearly defined chemical compound, 2 hydroxymethyloxolane (abbreviated HMO), having the structural formula and simple derivatives of this compound, alone and in combination with other carriers, give unique and unexpected results. Color-fastness, and especially resistance to bleeding in the printing of patterns, are excellent and, with some dyestuffs, significantly superior to other carriers. Use of HMO, and its derivatives, results in greatly improved and bulkier nylon yarns particularly suitable for carpeting. Natural and synthetic fibers demonstrate improvement in clarity of shade. Color yields corresponding to efficient discharge of the dyestuff from the dye bath run uniformly high with HMO and its derivatives. These compounds are generally water-soluble and readily compatible with other common auxiliaries present in dye 3 baths, and, in conjunction with these auxiliaries, produce excellent leveling. The use of HMO and its denvatlves has been found unexpectedly to produce rapid dyeing with excellent penetration, depth of shade, leveling and hand, also providing large economic savings over other effective carriers.

Additionally, the use of HMO and its derivatives 1n combination with other known carriers has been found to produce superior dyeing results while permitting use of lesser amounts of such other carrier. This is, of course, extremely beneficial in those instances where such other carrier is toxic or produces deleterious effects on the fiber. Thus, for example, in the case of dyeing bulk nylon (e.g., by the knit, print, de-knit process heretofore described), with some dyestuffs it has been found that HMO alone will not produce as deep a shade as 2% benzyl alcohol. However, a combination of HMO and 1% or less of benzyl alcohol produces superior results. This reduction in the quantity of benzyl alcohol necessary to produce otherwise satisfactory results greatly enhances the quality of the dyeing.

The beneficial effects described above are not limited to the HMO itself. Derivatives of HMO are also effective as carriers. A partial list of these derivatives is given below. This list is not intended to be exhaustive, but to indicate only the nature of the chemical relationship among these compounds.

2,3,4,5-tetrachloro-Z-hydroxymethyloxolane 3 ,4,5-trihydroxy-2-hydroxymethyloxolane 2-hydroxymethyl-5-methyloxolane 2-acetoxymethyloxolane beta-11ydroxyethoxymethyloxolane Z-methoxymethyloxolane The physical conditions under which these carriers and carrier blends are used can vary over ranges of temperature, pressure and percentage composition. Temperatures can range from about 110 F. to 300 F. depending on the fibers, dyestuffs, thickener and auxiliaries chosen. For dye bath temperatures from 212 F. to 300 F. suitable pressures must be applied, generally by steam. However, when dyestuif formulations are applied as a paste, for example by a padder or print roll, temperatures exceeding 212 F. may be employed using direct dry steam without elevated pressures. For example, in the aforementioned knit, print, de-knit process of dyeing nylon yarn, temperatures in the range of 212 F. to 235 F. are preferred.

The percentage of carrier or blend of carriers can vary from about 0.5 to 60% in aqueous-type media or higher otherwise, depending on the nature of the dye bath. These percentages are expressed in terms of the total composition of the dye bath. The lower ranges, about 0.5 to 48%, apply to systems in which water is the major solvent. The higher ranges apply to systems of solvents in water is present in minor proportions, or absent. Tlhgi carriers themselves can serve as solvents in the latter systems. When the carrier is employed as a vapor on a fiber, exposed previously to a dyestuif formulation, higher temperatures are preferred (about 180 F. to 260 F.) and the percentage of carrier in the vapor is also high (about 40% to 100% The following examples are presented to specifically illustrate the invention. These examples are not intended to limit in any way this invention, but are presented to give a working knowledge of same.

EXAMPLE I Knitted bulky nylon fabrics were printed with Acid Blue 15 ((1.1. 42645) using HMO alone as the carrier. The dye bath contained 5% dyestuif, 1% dispersant (sodium naphthalene sulfonate), 2% water-soluble natural gum, 2.5% HMO, 2% buffer (ammonium sulfate), the remainder being water. The carrier-containing dye composition was applied to the knitted fabric by a printing roll and the impregnated nylon then steamed at 230 F. with dry steam for six minutes. Washing and drying and then unraveling of the yarn therefrom produced a random dyed bulky nylon having superior bulk, superior crook-fastness and a deeper shade than material produced in the same manner using benzyl alcohol as carrier. With some other dyestuffs, although the bulk and crockfastness were superior, the depth of shade was lighter than with benzyl alcohol. In these latter cases a dye bath containing 1.5% HMO and 1% benzyl alcohol was found to retain the improved bulk and crock-fastness and to give uniformly deep shades of color.

EXAMPLE II The dyeing of Dacron polyester fabric with acetate dyestuffs was effected using a combination of HMO and o-phenylphenol as carriers. Dacron fabric samples were first scoured for 10 minutes at F. and rinsed well. The dye bath consisted of 1.5 H MO, 0.5% o-phenylphenol, 2% Disperse Yellow 42 (CI. 10338), 6% sodium dihydrogen phosphate, the balance being water. The HMO and o-phenylphenol were pro-mixed to give a uniform solution. This pre-rnix was then combined with onehalf of the water at 110 F. in the vessel to be used, followed by the sodium dihydrogen phosphate. The dye was dispersed in a small amount of water and stirred into the mix, which was then made up to its proper volume by the addition of water. The fabric was placed in this bath and the temperature raised to 212 F. and held there for 90 minutes. The fabric was then Washed with water, scoured, rinsed again and dried.

A comparison was made of the thus dyed fabric with other fabrics in which HMO was not used (or was replaced by a surfactant such as sodium dodecyldiphenyl oxide disulfonate). The fabric in which HMO was used showed distinctly deeper shades of color.

EXAMPLE III A blend of 65% Dacron polyester and 35% ArneP triacetate was dyed with Disperse Yellow 3 (CI. 11855) using both Z-acetoxymethyloxolane and a combination of Z-acetoxymethyloxolane and methyl salicylate. At low concentrations of carrier or carrier combinations (less than 10 grams per liter), shades were light and variable. At the recommended levels below, deep and uniform shades resulted.

Samples of scoured fabric were immersed in a dye bath containing 3% Disperse Yellow 3, 15 grams per liter 2-acetoxymethyloxolane (pre-mixed with 20 grams per liter emulsifier, sodium dodecyldiphenyl oxide disulfonate). The bath temperature was raised to 210 F. and maintained for one hour. Rinsing, scouring and drying the fabric samples produced dyeings in almost all cases with color value uniformly equivalent to or greater than control samples prepared from dye baths containing methyl salicylate as carrier. With those few dyestuffs giving better color values with methyl salicylate (10 grams per liter) than with 2-acetoxymethyloxolane, a combination of carriers (5 grams per liter of Z-acetoxymethyloxolane and 15 grams per liter of methyl salicylate) gave equivalent resu ts.

EXAMPLE IV Wool fabric samples after scouring were dyed with Acid Yelow 121 (C.I. 18690) using beta-hydroxyethoxymethyloxolane as carrier. Swatches were heated for 15 minutes at F. in a bath at pH 5.5 containing 1% Acid Yellow 121, 75 grams per liter of beta-hydroxyethoxymethyloxolane. A uniform discharge rate was observed in the bath. The samples after rinsing, scouring, rinsing again and drying showed deeper shades than samplesdyed with a bath containing benzyl alcohol as a carrier.

As can be seen from the foregoing, the use of HMO or its derivatives alone as a carrier produces enhanced results in many instances and eliminates the deleterious effects inherent with other known carriers. Additionally, when used in combination with other carriers, where desirable, the HMO or its derivatives permits the reduction of the quantities of such other carriers necessary to produce such results.

The present invention has been described in detail above for purposes of illustration only, and is not intended to be limited by this description or otherwise, except as defined in the claims.

What is claimed is:

1. A process of dyeing nylon fibers comprising applying to the fibers in an aqueous medium the mixture of:

(1) benzyl alcohol constituting no more than about 1% of the total composition of the aqueous medium,

(2) an acid dyestuff composition, and

(3) a methyloxolane carrier comprising a 2-hydroxymethyloxolane, constituting no more than about 2.5% of the total composition of the aqueous medium, and maintaining the fibers in contact with said mixture at a temperature and for a time suflicient to insure dyeing of the goods.

2. A process according to claim 1 wherein the nylon fibers are bulky nylon yarns in fabric form, and wherein said mixture is applied to the fabric by printing onto the fabric.

References Cited UNITED STATES PATENTS OTHER REFERENCES Diserens, Chemical Technology of Dyeing and Printing, pp. 207-209, 270-271, published 1951 by Reinhold Pub. Corp.

20 DONALD LEVY, Primary Examiner US. Cl. X.R. 8175 

